57- 



SCIENTIFIC NEWS. 



[Dec. 7, i? 



place, and the numerous holes for the two joints were 

 perfectly true. The operation thus succeeded with a 

 precision which might almost be regarded as mathe- 

 matical, considering the magnitude of the work and the 

 conditions under which the erection had to be performed. 

 We have only to mention the trials which took place 

 in April last, before the viaduct was opened for traffic. 

 These trials were of two kinds : in the one the loads 

 remained stationary, and in the other they were rolling. 

 The trial loads consisted of a locomotive of 75 tons, draw- 

 ing trucks of 15 tons each, and the results obtained show 

 the exceeding firmness of the work. The arch, loaded over 

 its entire length with a train of 22 trucks, weighing 405 

 tons, showed a deflection of only 8 millimetres. The 

 same train, placed upon one of the half-lengths of the 



One has only to take up the study of any special 

 branch, and he will first be astounded at his own ignor- 

 ance, and then, as he perseveres and obtains some grasp 

 of the labours of previous workers in his line of research, 

 he will before long come to see that the air, earth, and 

 sea have not yet yielded up all their storehouse of trea- 

 sures, and that there is still room for original investigation 

 in every branch of natural history. 



In our own time a remarkable stimulus has been given 

 to the study of biology, especially through the life and 

 works of that greatest of naturalists, Charles Darwin ; 

 and with such a brilliant example before us of quiet, 

 patient investigation, extending over so many fields of 

 nature, we may well be encouraged to persevere in the 

 study of any one special subject. The choice will de- 



arch, caused a deflection of only 4 millimetres at the 

 crown, and finally, under the action of the rolling load 

 the deflection was only 12 millimetres. 



SOME RECENTLY DISCOVERED FORMS 

 OF MICROSCOPIC CRUSTACEA. 



A LTHOUGH it may with perfect truth be said that 

 - *• there is nothing new under the sun, it is no less 

 true that there are many things which have hitherto 

 escaped the ken of our senses both in the organic and 

 inorganic worlds. 



Even were it not so, and everything above and below 

 the earth were known and tabulated, the zoologist, 

 botanist, and geologist would still find endless occupation 

 in studying the life history, histology, and composition of 

 this multitudinous variety of life and matter spread out 

 before us. 



pend upon the particular taste or environment of the 

 individual. 



To those of us who reside near thesea board, great oppor- 

 tunities are ready at hand — stones and rocks at low water 

 being sure to furnish material from all the divisions of in- 

 vertebrate life ; and the possession of a boat and dredge 

 will ensure the capture of forms unaffected by tides. 



It is proposed in this paper briefly to describe and 

 illustrate several species of minute marine Crustacea 

 which Mr. Isaac C. Thompson, F.L.S., has recently dis- 

 covered, taken principally by means of the tow-net in the 

 waters about our west coast. 



They all belong to the Copepoda, an order of the Ento- 

 mostracn, of the great class Crustacea, the Copepoda being 

 probably the oldest and most degenerate members of the 

 class. 



They are not at all confined to salt water, many species 

 being common in our ponds and lakes, of which the 

 cyclops is perhaps the most familiar example. Indeed,'it 



